The millions of people taking calcium supplements to strengthen their bones may be increasing their risk of a heart attack, a study in BMJ has found. The meta-analysis of 11 clinical trials involving 12,000 people found those taking 500 mg more more daily of supplemental calcium had a 30 percent greater chance of a heart attack over about four years than those who took no extra calcium. About 2.7 percent of participants taking a calcium supplement had a heart attack, compared with 2.2 percent of those taking a placebo. The average age of study participants was 72, and most were women.
ACSH's Dr. Gilbert Ross says while more research is needed, physicians may want to rethink how often they recommend calcium supplements for older women. "If someone has osteoporosis — as documented by bone density or previous fractures — then it's one thing, but almost anybody over the age of 50 or so, especially thin white females, is at risk for osteoporosis. I'm not saying this is practice-changing at this point — but it certainly is food for thought."
On a broader note, ACSH's Jeff Stier says this calls into question the whole notion that supplements are always good for you. "Every 'natural' biological mechanism that can help you, can also potentially hurt you, just because it's biologically active," he says. "But people have a tendency to think that if a little is good, more is better, and it ain't necessarily so."